The market for displays and other devices (e.g., keyboards) having non-mechanical touch functionality is rapidly growing. As a result, touch-sensing techniques have been developed to enable displays and other devices to have touch functionality. Touch-sensing functionality is gaining wider use in mobile device applications, such as smart phones, e-book readers, laptop computers and tablet computers.
Touch systems in the form of touch screens have been developed that respond to a variety of types of touches, such as single touches, multiple touches, swiping, and touches. Some of these systems rely on light-scattering and/or light attenuation. While effective, there remains a need for alternative optics-based approaches to touch-sensing that can provide the required sensitivity to sense one or more touch events and to determine the locations of the one or more touch events.